Calcium or total hardness is an important part of balanced pool water.

Too low and the water will eat away the liner, fiberglass or concrete.

Too high and you end up with scale.

So, here are the ideal levels for the various types of pools:

  • Vinyl pools 175 - 225ppm
  • Fiberglass pools 175 - 225ppm
  • Concrete pools  200 - 275ppm

Concrete pools need a higher level, otherwise the water will literally eat away the concrete.

It only needs to be raised once a year in the spring, specially for N2O users, since it requires a 200ppm total hardness to work properly.

If you are using liquid chlorine or the granular form of calcium hypochlorite, then the level of calcium or total hardness will raise every time you add that chlorine, thus reaching double the required ppms by June and scale will need to be taken care of, otherwise the scale build up will cause problems.

For salt pools, some will produce a high calcium chlorine and since all salt pools produce scale, better be careful with that level of total hardness.  There is a line of product specifically for salt pools that will help control that scale.